Planning for Warmer Weather

An engineering firm is anticipating the future effects of global warming and sends a team down to the South Pole to bore through the ice cap and take a 10-foot long sample of the Antarctic soil immediately underneath the ice cap, so it can plan its building projects once the ice cap has melted away. The team brings the sample back for testing, and determines that the soil has an average particle size of 58 microns, is suitable to support a 10 story building using standard foundation techniques, and is light gray in color. The firm then sends the team to the North Pole, where they also drill down through the ice cap and take a sample from the 10 feet immediately underneath. Upon testing, they determine that the particle size is much smaller than the particle size from the South Pole sample, and that the sample material is not suitable to support standard building techniques. What color is the North Pole sample most likely to be?